摘要
通过浸渍-焙烧的方法制得铁改性活性炭,并将之应用于废水中甲醛的吸附。分别考察了吸附时间、初始溶液质量浓度、吸附剂投加量对改性活性炭吸附甲醛效果的影响,并研究了铁改性活性炭对甲醛水溶液的等温吸附及动力学。结果表明:在25℃、活性炭投加量为10 g/L、吸附时间为360 min时,铁改性活性炭对甲醛的去除率为91.8%;用准一级、准二级及内扩散动力学模型拟合吸附过程,准二级动力学模型符合该吸附过程;用Langmuir和Freundlich模型描述等温吸附过程,该吸附过程服从Langmuir模型,饱和吸附量为3.396 7mg/g。
The given paper wishes to bring about the impregnation-calcination method initiated by the present author by way of using the iron modified activated carbon to remove the formaldehyd from the sewage. As is well known,modified activated carbon has been widely used for formaldehyd adsorption in water bodies,though it is uncommon by using the iron modified activated carbon. To achieve this purpose for preparing iron-modified activated carbon,we have studied a lot of influential factors,such as the adsorption time,the initial formaldehyde concentration,the p H value of the solution,the amount of the activated carbon to be used for the purpose of impregnation-calcination,and so on. Besides,we have also measured the kinetic data and the equilibrium sorption isotherm in batch-experimental conditions. The results have shown that the iron modified activated carbon in a position to adsorb formaldehyd in an efficient way. What is more,it has been found that the removal rate of the formaldehyd onto the iron modified activated carbon has been increased with the increase of the adsorbent dosage but the decrease of the initial formaldehyde concentration. Furthermore,the balance condition or that for equilibrium has been found by the time when the adsorption of formaldehyde by iron modified activated carbon reaches at about the time-duration of 360 min. The other data concerned we have achieved can be illustrated as follows： the maximum formaldehyde removal rate： 91. 8% when the temperature is 25 ℃,the adsorption time should be 360 min,with the adsorbent dosage being 0. 5g and the concentration of formaldehyde—30 mg / L. We have also tried the three simplified kinetic models,that is,a first-order equation,the pseudo-second-order and the diffusion model suitable for the sorption process,which follows a pseudo-second-order kinetics model. Moreover,we have also worked out the adsorption rate constant at about 0. 004 3 g /（mg·min）,which tends to increase with the increase of the initial formaldehyde concentration.In addition,the inherent diffusion has been found not the only control step,which is affected by the adsorption mechanism restriction. And,finally,we have taken Langmuir and Freundlich models to describe the sorption equilibrium data. All in all,the results prove that it would be made possible for the equilibrium for the adsorption of formaldehyde from the aqueous solutions by iron modified activated carbon to make fit to Langmuir type of isotherm equation. The maximum adsorption capacity for formaldehyde by iron modified activated carbon has been found to be qm= 3. 3967 mg / g,with the optimum adsorption p H being 6-8.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2015年第1期188-192,共5页
Journal of Safety and Environment
基金
国家自然科学基金项目(41163007)
广西自然科学基金项目(2012GXNSFAA053036)
广西教育厅项目(2013LX156
201010LX505)
关键词
环境工程学
铁改性活性炭
甲醛废水
吸附
动力学
environmental engineering
activated carbon modified with iron
formaldehyde wastewater
adsorption
dynamics
